Automatic firearm



H. W. GABBETT-FAIRFAX.

AUTOMATIC FIREARM.

APPLICATION FILED APH.22, 1920.

H. W. GABBETT-FMRFAX.

AUTOMATIC HREARM.

APPUCATIUN min APR. 22. 1920.

Patented July 6, 1920.

2 SHEETS-SHEET 2.

, Vn l Y M Nm i 41. n Fl" w f HUGH WILLIAM GABBETT-FAIRFAX, OF LONDGN,ENGLAND.

AUTOMATIC FIREARM.

Specification of Letters Patent.

Patented July 6, 1920.

Application led April 22, 1920. Serial No. 375,824.

To all whom it may concern Be it known that I, HUGH WILLIAMGAmiE'r'r-FATRFAX, a subject of the King of Great Britain, residing atLondon, England, have invented new and useful Improvements in AutomaticFirearms, of which the Jfollowing is a specification.

rlhis invention relates to automatic or semi-automatic firearms ingeneral (whether machine guns or small arms) of the kind in which thefirearm is operated by the shock of recoil and in which the breech,barrel, and breech-closing mechanism recoil while firmly lockedtogether, and provides means Jfor uncoupling the breech mechanism fromthe breech at any desired point in the recoil of the latter, after whichthe breech is opened and the empty cartridge case is ejected in theusual manner and the barrel and breech return to their forward positionof rest.

Hitherto the practice in the design of recoil-operated firearms has beenthat the mechanism for maintaining the cartridge in place in the breechhas been liberated by one of two methods; either the mechanism formaintaining the cartridge in place in the breech has been liberated atan early stage in the recoil of the breech, the breech being checkedwhile the bolt or breech-closing mechanism has still sufficient rearwardvelocity to unlock the breech, withdraw the cartridge case from thechamber and compress a sprin for returning the mechanism and closing t ebreech, and in this case the limited recoil available hasled tounlocking of the breech and extraction' of the car tridge case whilethere wasstill considerable pressure in the chamber with attendanttroubles due to torn cartridge cases and faulty extraction; or thebreech has been allowed to recoil to its fulllimit after which thebreech closing mechanism has been liberated and held back fwhileallowing the breech to' return to its position of rest,thebreech-closing mechanism being subsequently carried forward and,again connectedy with the breech. Inthis case the long travel of thebreech causes lossoftime'ibetween successive shots and considerablydecreases the possible rate of ,fire of the weapon.A

Itis the object of the present invention to provide means for allowingsuicient time to elapse between the firing ofthe weapon and theunlocking of the breech without using a longer recoil than is actuallynecessary. For this purpose I attach to the barrel, breech, or slidingcarriage connected thereto, a piston so arranged that the effort ofrecoil will compress a vohnne of air in a cylinder from which, at anydesired point in the recoil, a quantity of compressed air is takensuiiicient to uncouple the breech mechanism from the barrel and to forcethe said mechanism to the desired length oi" its travel and to returnthe barrel to its position of rest. The compressed air may also be madeto compress springs for returning the barrel and breech mechanism at anyde sired point. Also, it the energy of recoil bc sulicient, thecompressed air may be made to return the breech mechanism, and reload,close and lock the breech.

The accompanying drawings show two methods of applying the aboveprinciples to a machine gun, and it is evident that a similar method ofoperation may be applied to any other automatic or semi-automaticfirearm operated by means of a recoiling breech.

Figure l is a longitudinal section showing one method of applying myinvention to a irearm of the kind in which the breech and barrel recoilwhile firmly locked together as already described. The breech in thisarrangement is opened by compressed air and closed by a return spring.It is shown closed in the drawing.

Fi 2 is a transverse section taken on X (Fig. l) showing one method ofarranging the breeclrclosing mechanism shown in Fig 1.

Fig. 3 is a longitudinal section showing the same firearm as in Fig. 1but with the breech open. y

Fig. 4 illustrates in longitudinal section a modified arrangement iuwhich the breech is'both opened and closed by compressed air.

Figs. 5, 6 and 7 show various positions of the valves employed in thearrangement shown in Fig. 4 for a purpose hereinafter described.

Referrin to Figs. 1, 2 and 3, the barrel A is carried in, or is integralwith a breech B which may be integral with, or attached to a carriage B2sliding in guides B' in the main framing C. The said carriage B2 carriesat its forward end a bracket D which les may be integral with orattached to the cwrriage. A piston E working in a fixed cyl inder (i isattached by the rod F to the bracket D .amd therefore .moves with xthebreech and barrel. The cylinder (i is open to the atmosphere by a port Hin the eide of the cylinder when thc barrel is in its for ward poeition(eee Fig. 1) but is closed as soon as recoil begins.

The barrel is rc fistcrcd in its Yforward [1osition by a stop xr whichnay be .a fixed stop as shown, or any suitable vforni oi.' ,hydraulic,pneumatic or spring butler.

The air compressed by the ,piston E` paesee through a non-return valve Linto a tube M which is arrzmged with a sliding joint. Said tube Mcommunicates through a valve N with a cylinder() which ie preferablyintegral with, or attached to, the carriage B2 but can be attached tothe framework oi' the gun ifsnitablc modifications are made in theconnection M and valve N. The Said valve N mayr 'be a sliding valve asshown or oi" any other .suitable type which will perform the sainefunctions.

piston l Works in the cylinder and is norlnalhY held in its forwardposition by a spring l and said piston is attached by a rod P2 to an armQ formed en or attached to a known form oi' Cain plate which serves tounlock the breech bolt.

The bolt R is preferably carried in a sleeve S which slides Qin guides Sfol-ined in, or on, the inain framing C, and a radial arm R ,ri idlyattached to the bolt B Works in ,e slot 2 formed in the cam plate Q. Thebolt ll can rotate in the Sleeve S but 'has no motion of translationrelative ,to it,

'When rthe earn plate Q is drawn back relatively to the sleeve S thebolt R is rotated and the breech is unlocked, and When the cani plate Q`is drawn torwa rd relatively to the sleeve S the bolt ris rotatedjlocking said bolt into the lbreech. The cam plate Q slides in lguidesformed in or on or attached to the main framing (l or .the `sleeve S.

The Valve N is opierateil` by `means of a rod T which is attached tosaid valve, and Slides in a bearing formed in the earn plate arm Q' asshown, `or in the main Training, Said rod T has two arms ll and Vattached to it; the Iarm Il projects into the .cylinder O and is pushedbackward 'by the iston I when said piston reaches the end ofV itsbackward stroke, and the arm V is arranged to come into contact with esprin '.St l for the purpose of actuating the va' ve at any desired dintin the recoil.

A cylinder "Y lis formed in the breech earriage B2 and a piston Z worksin it. Said 'ston Z 'is connected by a rod 'ZE to the ramework of the unand has a return spring Z introduced between ,it and the for- Ward endof the cylinder.

If preferred, the piston may be yattachefli to the Jbreech(.'afrriagegand tney yWadi in a fixed (.fylinder attached to theframework ol the gun. The l'unctioninr is as iollows:-

lll/Then a shot ie tired,y Ahe barrel i`\ and breech B with the bolt ltlSecurely locked into it, recoil, and the pieton ll is driven backcompressing the air in thc cylinder (i and forcing the compressed airIthrougll the non-return Valve li into thc tnbc M. The recoil alsocompri-Fece the spring;- Z and this spring serres to return the barrelto ite forward position.

During the irst 1part of the recoil, the valve N 1s Set so that .thecylinder (1) is open to the atmosphere .through ports YO and N andopening N"o as shown in Fi ,l1 and is not in communication with .the tune M. The breech therefore remains locked.

lV hen the arm V engages with a stop YV the vvalve N is momentaaillt7checked, while the cylinder U continues to recoil. Ethue closing?r thccylinder to atmosphere .and connect ing it with thc tube M throuigh aport N2. Further recoil of the cylinder U causes the arin V to push the:atop W backward and downward against the action of ite eprinc`y andafter `a shout backward .increment the arm V becomes disengaged fnolnthe Stop l and rides over it. i

The compressed .air in front of .the lpieton f P drives the piston backrelativcly .to the l;)reecl1-cen1preesin g eprin P and also drives backthe cam plate which Afirst rotetes and unlocks the bolt It fand :then.retnacts it, thus opening the breech.

The breech can ,lee allowed a further .short recoil after the bneeeh isopened, or it may 4be checked at once., ,either by a fixed Step or by Sopro ortionin-g the springr Z that the energy o recoil is expended just,after .the breech is opened. In either case the spring Z expands endreturns ,the breech to its forwand pesition against ,the stoep K. Thepiston P is driven back by the .coulpressed air till it reaches thefendof its travel and then pushesV back .the arm U whichshifts the Valve Nvand thus closes the connnunication between .the cylinder ,amd the.l'tube M and opens Seid cylinder to the atmosphere. The spring Pi nowexpands thus closing the ,breech and locking thebolt.

During the forward motion .the arm V tneads down the s )ring toe of the,stop W and runs over it. e stop VST may hare any suitable form but musthe y .able 0f trip Puig the valve N at `any dsiired point m the recoilwithout interfering with the SubteV nentmotion. l

loading may be performed by any saitY able mechanism actuated lby the`slefieve in lts forward movement, .and cycle .utopera'tions is 'thenrepeated. Suitable ,spring stops or detente may be introduced to retainthe vclve pos'itionbetween one Ymovement and the next.

Lil

Referring to Figs. 4, 5, (S and 7 The construction here shown differsfrom that in Fig. l in the arrangement of the cylinder 0 and of theinlet and exhaust valves controlling the breech mechanism.

The return spring P (Fig. l) is dispensed with and compressed air isadmitted to either end of the cylinder as required.

P3 is an arm carried on the piston P2 and presses against a springplunger I4 when the breech is closed. This, as will be readily seen fromthe drawings, has the eilect of opening the rearward end of the cylimler(i) to atmosphere through the space around the arm P3, and cutting oh'the air supply from this end of the cylinder till such time as it isrequired. The valve N is arraiiged to control both ends of the cylinderand functions as already described.

When recoil begins, the valve N is in its rearward position as shown inFig. 4, and the forward end of thc cylinder is therefore open to theatmosphere through the passage shown. The rearward end ot the cylinderwould be in communication with the tube M ii the plunger P4 were notinterposed, but this plunger is in its forward position closingr therearward branch of connection tube M and preventing the setting up ofhackprcssurc and consequent waste et compressed air during the firststage of recoil. Then the arm V engages with the spring stopi N thevalve is held back momentarily, and admits air to the forward end ofcylinder (l while closing that branch of tube M which communicates withthe rearward end ot said cylinder. as shown in Fig. 5. Subsequently thearm V runs over the stop l as already described with reference to Fig.l.

The compressed air now drives the piston P to the rear, thus opening thebreech and causing the arm P3 to become disengaged 'from the plunger l,whereupon said plunger is Vforced rearwardly by its control. spring. Therear cud of the cylinder is innncdiately placed under the control ol thevalve N as shown in Fig. (i.

t the end of its rearward travel` the piston l) pushes the arm V to therear, thus opening the forward end of the cylinder to the atmosphere.and admitting compressed air to the rearward end of the cylinder asshown in Fig. 7.

The piston l is now dri von forward and the breech is closed and locked,the plunger l being returned to its forward position by the pressure ofthe arm P3.

In other respects the arrangement shown in Figs. 4 to S is similar tothat shown in Figs. l to 4.

If the locking and unlocking of the breech be completed before thebarrel has gone tar on its forward journey, the non-return valv .l L maybe dispensed with, otherwise it is essential, as without it the pressuredue to the compression ol' the air might be lost before the operation ofthe breech mechanism was complete. The connection tube M may he made ofsu'llieient size to store the necessary quantity of compressed air atthe desired pressure, or a container or receiver may be introduced intothe tube M at any suitable point, the tube and container together havingthe necessary storage volume.

lt is evident that the modification shown in` Fig. amay be furtherextended, and that compressed air may he used to return the barrel aswell as the bolt and sleeve, thus dispensing` with return spring Z. Ur,il the cylinder (l bc made oic sutlicient size, the pressure oi the airin its forward end may be sldiicicnt to drive the rccoiling partsforward at thc same time as it drives the bolt back. In that case, astop o1' butler similar to l would be lixed at the rear end oi the gunto hold up thc slcerc or cam plate at the end oi' its trawl and the airwould remain in the iorwal'd cud of the cylimler (i) tii the barrel hadgone home. The parts 1. 14, .'fj, Z2 would thus be dispensed with.

lihat l claim is l. ln a lirearm, a. rccoiling breech and barrel, anair-cylimlcr, a piston movable in said cylinder, gearing connecting saidpiston to said breech and barrel. means for taking compressed air fromsaid cylinde at any desired point in the recoil, breech mechanism. meansactuated by such compressed air for (nierating the breech mechanism andopening the breech, and means `l'or ciesing the breech and returning therecoiling parts of the firearm to their forward position.

E2. In a firearm, a reeoiling breech and barrel, an air-cylinder. apiston movable in said cylinder. gearing connecting said piston to saidbreech and barrel, means for taking compressed air Vfrom said cylinderat any desired point in the recoil, breech nicchanism, means actualcd bysuchcompressed air l'or operating the breech mechanism and opening thebrccch, and means actuated by compressed air Jfrom said cylinder forclosing and locking the ln'cech.

Il. ln a firearm.` a recoiling breech and barrel, an air-cylinder. apiston movable in said cylinder. gearing connecting said piston to saidbreech and barrchmcaus for tal(- ing compressed air 'from said cylinderat any desired point in the recoil. breech meehanism, means actuated bysuch compressed air for operating the breech mechanism and opening thebreech and also for returning the whole of the reeoiling parts of thefirearm to their forward position, and simultaneously closing andlocking the breech.

4. ln a firearm, a recoiling breech and barrel. a carriage combined withsaid breech and barrel. a frame haring guides in which said carriage isslidable, an air-cylinder fixed to Said frame a pieton movable in Saidcylinder and eonneeted. to said carriage, said piston being adapted toopen a port in said cylinder when the bai'iel ie in its 'forwardpoeition and to Close. Snell poi-i ae' soon aS the rei-oil begins, anair-eyliinler movable with tln` warriag'e. a conduit connecting saidiixed and movable ail' eylinilers, a non-return nlve in Said conduiteontrollin` the outlet of Asaid lined air Cylinder, a piston in themovable air evvlinder,y means eonnerfted to the piston in Said movableair eylinder for nnlowkingv and loeliinj;l the lneei-li bolt` a valveeontrolling; the conduit between the lived and movable air evlindere, arod eonneeted lo said valve, an arm on Said rod adapted to be engaged bythe pieton in the movable air Cylinder and an arm on. said rod adaptedto be engaged b v a etationai)i Stop, and means l'oi returning theeaxiiage and attached parte to their forward posi tion.

ln a lirearm` a reeoilin;y breeeh and ba rrel, a carriage eombined witheaid breeeb and barrel. a frame having ,guides in whieli the varriaggeelidable` an air-cylinder fixed to said frame. a piston movable in Saidelvlinder and connected to Said carriage, said piston being adapted toopen a port in Said Cylinder when the barrel is in its forward positionand to elose Snell port as soon as the ref-oil begins, an air cylindermovable with Said Carriage, a Conduit eonneetinnr the ontlet of saidfixed ai: cylinder and the ende of the movable air cylinder, anon-return valve in said eondnit controlling the outlet oi the lixed aircylinder, a piston in the movable air cylinder, means connected to thepiston in the movable air cylinder for unlocking and locking the breechbolt, a valve Controll ing the conduit between the fixed and movable aircylinders, means operated by a naeeo 12 xed stop and by the piston ol'the movable air cylinder `for actuating said valve, a suplen'ientaryplunger-valve controlling the eommnnieation between the conduit and oneend oi' said cylinder, said pli1ngervalve being actuated by the pistonof the movable air evlinljler, Substantially as and for the pnl-posesSpecified.

6. ln a ireai'm, a roeoilingr breech and barrel, a Carriage eombinedwith said breeeli and barrel, a trame having guides in which theear-ringe slidable, an air emvlindei' lixed to said trame, a pietonmovable in said eylinder and eonneeted to :laid earriager` Said pistonbeing adapted to open a port in said o vlindei when the barrel is in its'forward position and to eloee elleli port as soon as the recoil begins,an air cylinder movable with the carriage, a eondnit eonneetingr said.l'ixed and movable Cylinders a noinretnnn valve in said conduitcontrollingl the outlet of Said fixed air riyliniiler a pieton in themovable air cylinder, a sleeve slidable in guides on the frame, abreech-bolt rotatable in said Sleeve, a radial arm on said bolt, a Cainplate Slidably mounted on Said frame and having?Ir its eam surfaces inengagement with Said radial arm, a connection between said earn plateand the piston ol" said movable air cylinder, e valve Controllingr theconduit between the fixed and movable air cylinders1 means for operatingSaid valve actuated by the piston in the mo Table air cylinder and by anelastic stop, and means; for returning the carriage and attached partsto their forward position. i

26th Mareh, 1920.

HU GH WILLIAM GA BRETT-F A1 RFAX.

lvitnesses EDWARD SinNnY RoYs'roN ADAMS, Gnomiz Homann Ginn'ox SHEPHERD.

